Apparatus for driving actuator of camera module in mobile device

Abstract

Embodiments of the invention provide an apparatus for driving an actuator of a camera module in a mobile device. The apparatus includes a proportional-integral-derivative (PID) controller configured to compare an output of a gyro sensor with an output of a hall sensor configured to sense a position of an actuator to output a digital signal of plural bits, and a differential current digital-to-analog converter configured to convert the digital signal output from the PID controller into an analog current signal. The apparatus further includes a linear driver configured to receive the signal output from the differential current digital-to-analog converter to output a linear driving signal, an H-bridge circuit configured to control magnitudes of a forward driving current and a reverse driving current flowing in the actuator based on the output of the linear driver, and a driving direction controller configured to output a signal controlling a direction of current flowing in the actuator to the H-bridge circuit based on the digital signal output from the PID controller.

Description

CROSS REFERENCE TO RELATED APPLICATION[0001]This application claims the benefit of and priority under 35 U.S.C. §119 to Korean Patent Application No. KR 10-2014-0029166, entitled “APPARATUS FOR DRIVING ACTUATOR OF CAMERA MODULE IN MOBILE DEVICE,” filed on Mar. 12, 2014, which is hereby incorporated by reference in its entirety into this application.BACKGROUND[0002]1. Field of the Invention[0003]The present invention relates to an apparatus for driving an actuator of a camera module in a mobile device.[0004]2. Description of the Related Art[0005]A camera module in a mobile device, such as a smart phone, a tablet PC, and a camera has extendedly applied functions, such as an auto focus (AF) and an optical image stabilizer (hereinafter, referred to as an OIS) to obtain a high-definition image. Therefore, a linear current driving technology of an actuator, such as a voice coil motor (VCM) for low noise among core technologies for implementing the AF and OIS functions, has become increasi...

AI Technical Summary

Benefits of technology

The invention provides an apparatus for controlling an actuator in a mobile device with greater accuracy and speed. It uses a differential current digital-to-analog converter and a linear driver to control the position of the actuator by controlling the forward and reverse current of the actuator. This allows for linear current driving based on the resistance and transistor gate width ratios, which are less affected by temperature and process changes.

Problems solved by technology

However, the small resistance value is difficult to be accurately implemented within the actual IC and sensitively reacts to a temperature change and a process deviation, such that it is difficult to obtain stable performance.

Images